1. The issuer's "ADSs" are American Depositary Shares, with each ADS representing one ordinary share, nominal value $0.01 per share, of the issuer; ADSs may be represented by American Depositary Receipts.

2. The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $9.188 to $9.19, inclusive. The reporting person undertakes to provide to Avadel Pharmaceuticals plc, any security holder of Avadel Pharmaceuticals plc, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the ranges set forth in this footnote (2).

3. Includes (a) 20,000 restricted ADSs granted under the issuer's "Free Share" award program on 8/10/2016, all of which will be issued to the reporting person on the second anniversary of the grant date; and (b) 10,000 restricted ADSs granted under the issuer's "Free Share" award program on 12/14/2016, all of which will be issued to the reporting person on the second anniversary of the grant date.

4. The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $9.317 to $9.39, inclusive. The reporting person undertakes to provide to Avadel Pharmaceuticals plc, any security holder of Avadel Pharmaceuticals plc, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the ranges set forth in this footnote (4).

5. The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $9.143 to $9.15, inclusive. The reporting person undertakes to provide to Avadel Pharmaceuticals plc, any security holder of Avadel Pharmaceuticals plc, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the ranges set forth in this footnote (5).

6. The filing of this statement shall not be construed as an admission that the reporting person is, for purposes of Section 16 of the Securities Exchange Act of 1934 or otherwise, the beneficial owner of these securities.

7. Options become exercisable as to 25,000 ADSs on each of the first four anniversaries after the 06/26/2015 grant date.

8. Options become exercisable as to 12,500 ADSs on each of the first four anniversaries after the 12/10/2015 grant date.

9. Options become exercisable as to 20,000 ADSs on each of the first four anniversaries after the 12/14/2016 grant date.

Remarks:

Sr. VP, Quality and Reg. Affairs.

/s/ Phillandas T. Thompson, as attorney-in-fact for Sandra L. Hatten

09/15/2017

** Signature of Reporting Person

Date

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person,
see
Instruction
4
(b)(v).